Roller blinds, or shades as they are sometimes referred to, are common forms of window coverings used in residential and commercial applications. Roller blinds are typically mounted within or exterior to a window frame by means of mounting brackets that are screwed or otherwise fastened to structural elements of the window, the window frame, a wall, or the ceiling adjacent to the window frame.
When mounting a roller blind or shade it is important that the blind be level or horizontal for not only obvious aesthetic purposes, but also to ensure a proper functioning of the blind. If the roller tube upon which the blind fabric is wound is not horizontal, the blind may tend to “telescope” on the roller tube as it is wound up. Excessive telescoping can cause the edge of the blind fabric to come into contact with a mounting bracket, which can result in damage to the blind material, or a binding of the roller tube to the point that the roller blind will not function properly.
It will thus be appreciated that careful and time consuming measurements are often required in order to properly mount a blind or shade. The degree of difficulty in mounting the brackets to hold the shade increases in situations where the existing window, window frame, wall and/or ceiling is not perfectly straight or perfectly plumb.
To assist in the mounting of roller blinds or shades, adjustable mounting brackets have been proposed. Such brackets allow for a degree of vertical movement of the ends of the brackets in order to assist in the horizontal leveling of the roller tube (see for example U.S. Pat. Nos. 7,854,419 and 8,967,568, incorporated herein by reference).
While such adjustable mounting brackets are of assistance in helping to properly orient the roller tube and to help prevent or limit telescoping of the blind fabric, should the blind fabric nevertheless telescope and contact the adjustment mechanisms that are commonly present in such brackets, the edges of the blind fabric could become damaged. The potential for damage to the blind fabric is enhanced in cases where relatively delicate or sheer blind fabrics are utilized.